1. Field of the Invention
The present invention relates to image forming apparatuses that discharge sheets for normal images and sheets for sample images.
2. Description of the Related Art
Conventionally, image forming apparatuses have been known to form images on sheets based on image data, and discharge the sheets on which images have been formed. The image forming apparatuses are, for example, copying machines or printers, etc. When the image forming apparatus is a copying machine, the image forming apparatus obtains the image data by reading out the image from an original document. On the other hand, when the image forming apparatus is a printer, the image forming apparatus obtains the image data from an external apparatus such as a personal computer, etc. In the following explanations, an image that is formed based on image data that is the object to be copied or printed out is called a normal image.
Here, there is a case in which the image forming apparatus successively discharges sheets on which normal images have been formed. For example, this is the case of carrying out image formation based on the image data of a plurality of pages, or of carrying out image formation of a plurality of copies based on the image data of a single page, etc. In such a case, if a situation occurs in which some abnormality occurs in the image quality of the images formed on the sheets, a large number of defective outputs may be generated, and therefore it is necessary to verify whether or not there is any abnormality in the image quality in the middle of carrying out successive image formations.
For example, image forming apparatuses have been known to discharge a sample image sheet which is a sheet on which a sample image has been formed (see, for example, Japanese Unexamined Patent Application Publication No. 2005-153374 and Japanese Unexamined Patent Application Publication No. 2005-157015). In such an image forming apparatus, the destination of discharging normal image sheets on which normal images have been formed and the destination of discharging sample image sheets are distinguished from each other.
However, in the image forming apparatus described above, even if it is possible to confirm that there is an abnormality in the image quality of the sample image formed on the sample image sheet that has been discharged, it is difficult to grasp at what time that the sample image sheet was discharged. In other words, it is difficult to grasp at what time the abnormality occurred in the normal image formed on the normal image sheet. In particular, in cases in which a large number of the normal image sheets are output from the image forming apparatus, it is still more difficult to grasp at what time the sample image sheet was discharged, and it is extremely difficult to grasp at what time the abnormality occurred in the normal image formed on the normal image sheet.
Further, although the user may constantly monitor the time at which the sample image sheet was discharged, in this case the load on the user is extremely high.